The influence of religion on Mesopotamian art and culture is exemplified by innumerable stelae, inscriptions and even accounting documents bearing some form of invocation. The gods played a central role in the life of every Mesopotamian, and from Sumerian times it was believed that they, as human beings, existed only to serve these gods . Samuel Noah Kramer writes that "life, they believed, is beset with uncertainty and haunted by insecurity, since man does not know beforehand the destiny decreed for him" (Kramer p101). In an effort to relieve this uncertainty Mesopotamian society turned to divination. Astronomy and astrology became among the most important and influential disciplines in the ancient Near East for their perceived ability to read the wants and needs of the gods directly from the sky. Mesopotamian cosmology held that the earth and the sky were connected and that the motion of the stars was a reflection of earthly events as well. The two were mirror images of one another. Thus the astronomer who understood celestial motion was able to see clearly the coming events of their terrestrial domain, allowing them to wield a certain amount of power in the court and influence in art and literature.

The official practice of astronomy in Babylon was secret and conducted by priests in the elevated privacy of ziggurrats. It was in the Old-Babylonian period, between 2000 and 1500 BC, that astronomy itself began to develop and grow in complexity. Its foundations lay with the Sumerians, whose simple logograms served to greatly facilitate the transcription of astronomical nomenclature, and whose mathematics made possible the cumbersome calculations the practice of astrology would require. Over time astronomical observations would evolve into an intricate maze of records and computations. As the observers advanced in skill, each generation after them was challenged to progress even further. A demand for interpretations of the omens the gods wove in the sky created the need to make more accurate predictions. Kings and their empires looked to astronomers for advice in making important decisions. A country's success in any campaign depended on divine approval, and the court astrologers provided a means to search for this support. From its functional beginnings in time reckoning, to the Chaldean's most impressive predictions of lunar eclipses, astronomy in ancient Mesopotamia stands as an excellent example of the extent to which people take their passion for the stars. Astronomers were skilled enough to notice the periodicity of celestial motion, draw from it their ability to make predictions, and thereby establish themselves as among the most influential people in the ancient Near East.

For the purpose of divination the astronomers monitored the motion of the stars and planets, compared their observations with the omens in Enuma Anu Enlil, and then explained that omen's relevance to the situation at hand. They monitored the Sun (Shamash) and the Moon (Sin), as well as the rising and setting of stars and constellations such as those listed in the astrolabes. In fact, every astral and meteorological event earned their scrutiny and presaged things relevant to the empire. Predictions were made as to when certain stars ought to rise, or in what phase the Moon ought to be. If the predictions were correct this was an auspicious sign. If, however, things did not occur as planned the omen was more menacing. At the very least it meant the calendar was off and corrections would have to be made. Texts such as Enuma Anu Enlil dealt with such extraordinary celestial behavior. By the time the omens contained therein were compiled under Assurbanipal, astronomers had a remarkably thorough reference with which they could compare their observations.

The astronomers also possessed exhaustive records of eclipses. Eclipses were especially foreboding to the king. In response to the divine wrath manifest in the eclipse the Assyrians took measures to install a "substitute king" to protect the true king's life. This substitute, put in place well in advance of the eclipse, would suffer the anger of the gods in place of the true monarch. How the Assyrian or other kings were to be effected depended on the conditions under which the eclipse occurred. If, for example, during a lunar eclipse Jupiter was visible, the king was in no danger. On the other hand the astronomer may write to the king a warning that "of the eclipse, its evil up to the very month, day, watch, point of light where it began and where the Moon pulled and drew off its eclipse- these concern its evil" (Thompson, No. 268). In this way the astronomers who could predict an eclipse helped protect the king's life. With enough warning the king's officials could find a substitute to free him from danger.

It is not surprising the astronomers of ancient Mesopotamia wielded a considerable amount of power when one considers that they were able to predict eclipses. This was a skill they possessed through decades of observation and careful record keeping. They commanded hundreds of tablets beyond the reach of the uneducated. All of this information was vital to their power of prediction and royal influence. It is not as if their advice was always taken. However in times of uncertainty and danger their council was frequently sought.

Nevertheless, it must be remembered that the astronomers were priests, and the principle motivation behind their strict observations was religion. It was their gods the astronomers viewed wandering across the night, and it was their moral obligation to attend to their bidding. Despite a vast history of recorded observations the astronomers never ventured to use this data to construct geometrical models of their universe. They never made and tested hypotheses. Mesopotamian astronomers did not apply their astronomical information to "scientific" questions distinct from religion. Rather, astronomy advanced as a function of religion, and it was of the utmost importance that they improve their science in order to better understand their gods. By the time the Assyrians came to dominate Mesopotamia and beyond, the practice of judicial astrology, relating the motions of the gods to kings and empires, was the crux of astronomy as a whole.

Their fame as astrologers spread well beyond the borders of Mesopotamia. They were loathed by the Hebrews as sacreligious sorcerers, and admired by the Greeks as skilled astronomers. Yet, despite their reputation, the Mesopotamians left behind them an enduring legacy of astronomy which is as impressive today as it must have been over 2000 years ago.